Plants require sufficient amount of water in the host soil to assist in absorbing minerals, and stimulate adequate growth. In such environments, air helps formation of desired solutions of compounds and minerals, which are subsequently absorbed through the roots and carried to the leaves of the plant.
Both water deficiency and also excess amount of water can adversely affect such process, and hence the plant growth. For example, excess water being added to the soil is not able to properly drain away, and thus occupies minute air spaces between soil particles. Consequently, air is prevented from reaching minerals in the soil, and cannot adequately combine therewith to form necessary nutrients for the plants. If this condition persists, affected plant will die. Accordingly, maintaining a proper balance between air and water in the soil and suitable moisture content are critical factors for plant growth.
Control of soil moisture content can become challenging in closed environments such as households and green houses. The Moisture content of soil that hosts the plants needs to be maintained at an optimum level to prevent plant loss or retardation of growth. Electronic signaling devices that monitor moisture content often are negatively affected through electrolysis and rusting of conductive parts. For example, minerals from fertilizers can readily deposit on conductive parts that measure electrical resistance associated with adjacent soil, and hence provide inaccurate readings.
Likewise, commercially available non-electronic devices which operate by a chemical dye—(e.g., turning color from pink to blue in presence of moisture, or by a dark green piece of plastic turning a lighter green in absence of moisture) suffer from poor visibility, are highly inaccurate, and have a short operating lifetime. Because these chemical dye devices rely on capillary action that passively transports moisture from the soil to the sensing area of the device, they are subject to corrosion and precipitation of salts and fertilizer within the device, an operating parameter which effectively destroys accuracy and usability.